1. Field of the Invention
The present invention relates generally to optical fiber, and more particularly to dispersion compensation fiber and transmission lines including combinations of NZDSF transmission fiber and dispersion compensation fiber.
2. Technical Background
Higher data rates and wider bandwidth systems are becoming needed for the telecommunications industry. Thus, the search for high performance optical fibers designed for long distance, high bit rate telecommunications that operate over broad bandwidths has intensified. These high data rates and broad bandwidths, however, have penalties associated with them. In particular, dispersion is a significant problem in such systems. More specifically, positive dispersion builds along the length of the high data rate transmission fiber. Dispersion Compensating (DC) fibers included in cable or in Dispersion Compensation Modules (DCM's) have been designed that compensate for such dispersion. These fibers generally have negative dispersion slope and negative total dispersion, with the dispersion having a large negative value such that a short length of the DC fiber compensates for the positive dispersion and positive slope of the longer transmission portion. For C- and L-band operation between 1525 nm and 1625 nm, the bend performance (both macro-bending and micro-bending) and other properties, such as dispersion and kappa linearity (kappa being the ratio of total dispersion divided by dispersion slope at a specific wavelength) of the DC fiber are very important.
Thus, there is a need for a DC fiber which: (1) exhibits fairly linear properties over the C- and L-bands in a wavelength range (1525 nm to 1625 nm); (2) retains the usual high performance optical fiber characteristics such as high strength, low attenuation and acceptable resistance to micro- and macro-bend induced loss, and (3) is particularly effective at compensation for the dispersion of low slope NZDSF transmission fibers across the C and L bands with low average residual dispersion.